Motor block and hypotension following a high thoracic erector spinae plane block.

Abstract

Dear Editor, Erector spinae plane blocks (ESPBs) are becoming more prevalent in clinical practice for postoperative pain control following truncal procedures. ESPBs are often quoted as being easy to perform and having few complications. We describe a patient with a thoracic epidural spread after administering an ultrasound-guided unilateral high thoracic ESPB for a video-assisted thoracoscopic procedure (VATS). A 62-year-old woman with chronic smoking, hypertension, and asthma was scheduled for an elective right VATS upper lobectomy for a malignant lesion. Her body weight was 78 kg, and she had no functional limitations. After obtaining informed consent, standard Canadian Anesthesia Society monitors were applied. She received preprocedural 1 mg of intravenous midazolam. The block was performed in the block room by an anesthesia resident under an experienced attending anesthesiologist’s supervision. In a sitting position, right ESB was performed using a linear ultrasound transducer oriented in the parasagittal plane. An out-of-plane approach was used due to the shorter needling distance, thus mitigating discomfort. After contacting the T4 TP, 20 ml of 0.5% ropivacaine was injected, and a local anesthetic was seen spreading deep to the erector spinae muscle. She was transferred to the operating room following an uneventful 10 min of monitoring in the block room. Upon directing the patient to move from the stretcher to the operating table, she noted having decreased bilateral lower limb sensation and motor weakness. Physical exam revealed decreased strength in hip flexion and a bilateral truncal sensory from T4 to L4 dermatomes. Her blood pressure had dropped to 73/36. She did not have any shortness of breath, chest pain, or light headedness. An awake radial arterial line was placed, and a phenylephrine infusion was initiated at 20 mcg/min. With her blood pressure stabilized, the decision was made to proceed with surgery. With surgical stimulation, she was able to wean off the phenylephrine infusion. She had no motor weakness or sensory loss following an uncomplicated 3 h long VATS lobectomy. In the post-anesthetic care unit (PACU), Pain scores were between 4 and 6, and blood pressure was 99/66. In a review, the incidence of complications of ESPBs is 0.2%, including bilateral lower limb weakness, motor block, transient apathy, aphasia, dizziness, loss of consciousness due to systemic toxicity and pneumothorax.[1] Selvi et al.[2] reported an unexpected motor weakness following bilateral T11 ESPB, and De Cassai et al.[3] reported near-complete lower extremity immobility following bilateral L3 ESPB for lumbar laminectomy. Our patient experienced bilateral motor and sensory block along with significant hypotension 15 min after a high unilateral thoracic ESPB. Given the symmetrical nature of the blockade and its resolution, we postulated that the local anesthetic injected had spread to the epidural space via the costotransverse foramen.[3] This may be related to the orientation and the angulation of the needle. Such a precipitous and unexpected drop in blood pressure could result in hemodynamic instability and cardiac compromise in some patients. Although seemingly rare, caution must be taken. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.